The present invention relates to a medical instrument particularly adapted for use in ophthalmic surgery. During extracapsular cataract surgery, it is necessary for the surgeon to perform many operations with small and delicate instruments viewed through a microscope. At the present time, the break-up and removal of the cataractous and other tissue from the eye, as well as the continuous substitution of fluids back into the eye to maintain appropriate internal pressure, is typically carried out with manually operated hand-held instruments. The delicateness and precision with which ophthalmic surgery is performed requires highly durable precision instruments which are capable of performing the same precise function in the same way every time.
Modern extracapsular cataract surgery involves the removal of the cortex of the cataract by an "aspirator" instrument while at the same time utilizes an infusion system for keeping the anterior segment of the eye filled with fluid and safe from collapse. The aspiration instrument removes the cortex and also engages and frees strands of cortex to either aspirate them or flush them from the eye using irrigation. A cystotome instrument is also utilized during cataract surgery to cut open the lens and assist in the removal of the cataractous tissue.
A variety of aspirating, infusion and cystotome systems and instruments are in use today for assisting in ophthalmic surgery, particularly extracapsular cataract surgery. Separate aspirating cannulas, separate sources of aspiration pressure, and separate infusion cannulas are often utilized in the same operation, although some surgeons use instruments which combine the aspiration and irrigation functions. Manually operated syringes to generate aspiration and control functions are also utilized. Not only do these systems often utilize separate devices to perform the various functions, but the devices usually require the use of both hands of the surgeon, leaving him without a free hand to perform other tasks or steady the instrument. Also, the required manual operation of these instruments is often tiring to the surgeon and can lead to some imprecision.
Pump mechanisms are often utilized to provide the aspiration, but these are usually controlled by foot pedals which are often complex to operate and sometimes difficult to find easily under operating room conditions. The foot switch activated pumps are also connected to the aspiration cannula by long flexible tubing which can cause fluctuations in the aspiration pressures and brief time delays in the operation of the instruments.
Present cystotome instruments for extracapsular cataract surgery are also typically manually operated. Again, these instruments can be fatiguing to the surgeon and could cause imprecision in the operation thereof.
The present invention has been developed and designed to overcome the problems associated with present systems and instruments for ophthalmic surgery, particularly extracapsular cataract surgery. It provides an automatically operated device which can be held and operated in one hand by the surgeon, provides the same precision function continuously and repeatably (of either aspiration, irrigation, or cystotome procedures), and utilizes disposable parts to maximize sterility and cleanliness.
It is an object of the present invention to provide an effficient, precise, easily operable instrument for use during eye surgery and removal of cataracts. It is another object to provide an instrument which can be held and operated in one hand by the surgeon and which does not utillize foot pedal controls or long tubing in operation. It is still another object of the invention to provide an instrument for extracapsular cataract surgery which utilizes disposable parts wherever possible, is lightweight, is reliable in performance, has variable speed controls, and has a back flush feature (for example, to release accidentally engaged tissue). A further object of the present invention is to combine convenience, flexibility and precise control for a procedure which demands optimization of all of the above-mentioned features for precision and safety.
In accordance with the present invention, a hand-held motorized instrument is provided which is operated by a battery-run control system. The body portion has a worm-drive mechanism for speed and direction controls, and is adapted to operate either an aspirator or cystotome instrument insert which is affixed in place in the instrument. As an aspirator, a syringe type mechanism is utilized with a coaxial aspirator-irrigator tip. The plunger of the mechanism moves in either direction, at a variable controlled rate of speed, and has a back flush option which automatically reverses the aspiration cycle when the control button is released. As a cystotome, the insert mechanism has a rotatable cannula tip which can be rotated in either direction, either continuously or one cutting stroke at a time.
Other objects, features and advantages of the present invention will be apparent from the following disclosure taken in conjunction with the accompanying drawings and appended claims.